The objective in breeding the present novel variety, assigned the denomination WINOLA, was to obtain a late ripening seedless mandarin citrus. In the spring of 1979 a controlled pollination cross between Wilking mandarin (resulting from a cross of King.times.Willowleaf (Mediterranean) made in 1915 and reported by H. B. frost in Calif. Agr. Exp. Sta. Bull, 1935, 597-601.) as a seed bearing parent and Minneola tangelo (resulting from a cross between Duncan grapefruit and Dancy mandarin produced in Florida by the USDA and named and released in 1931) as a pollen parent was made at the Agricultural Research Organization, the Volcani Center, Bet Dagan, Israel. The fruits were collected in November 1979. Seeds of these fruits were extracted and subsequently germinated during January 1980. About 16 seedlings were top grafted on a mature Valencia orange scion grafted on a Troyer rootstock growing in an experimental grove in the Acre Experimental Station, Acre, Israel.
The first fruits were observed in March 1984 and a second observation was made in February-March 1985. One of the 16 scions was selected and numbered 1-5-1. The fruits of this selection were orange red colored, seedless and they were fully ripe in March.
Budwood was taken from the above mentioned selection and top-grafted in the spring of 1985 on two Valencia orange scions grafted on Sour Orange rootstocks growing in an experimental grove of the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. The first crop of these trees was obtained in 1988. The yield was good and the fruit had an excellent flavor.
In the spring of 1988, five additional Winola trees grafted on Troyer rootstocks in the experimental grove of the Agricultural Research Organization, The Volcani Center, were also grafted with budwood from the above mentioned tree.